1. Field of the Invention
This invention relates to a lubricant composition containing an alkoxylated amine salt of a dihydrocarbyldithiobenzoic acid and its use to improve friction reduction in an internal combustion engine.
2. Description of the Related Art p In order to protect internal combustion engines from wear, engine lubricating oils have been provided with antiwear and antioxidant additives. The primary oil additive for the past 40 years for providing antiwear and antioxidant properties has been zinc dialkyldithiophosphate (ZDDP). U.S. Pat. No. 5,076,945 discloses a lubricating oil composition containing an amine salt of a dithiobenzoic acid. The amines used to prepare salts are long chain hydrocarbyl amines.
Oil additive packages containing ZDDP have environmental drawbacks. ZDDP adds to engine deposits which can lead to increased oil consumption and emissions. Moreover, ZDDP is not ash-free and contain phosphorus which poisons the catalytic converters of cars. This results in increased emissions. Various ashless oil additive packages have been developed recently due to such environmental concerns.
It would be desirable to have a lubricating oil additive which provides excellent antiwear, fuel economy and environmentally beneficial (less fuel, less phosphorus, i.e., less exhaust emissions) properties.